Willig, Katrin I.

[["dc.bibliographiccitation.artnumber","219"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Scientific Reports"],["dc.bibliographiccitation.volume","8"],["dc.contributor.author","Wegner, Waja"],["dc.contributor.author","Mott, Alexander C."],["dc.contributor.author","Grant, Seth G. N."],["dc.contributor.author","Steffens, Heinz"],["dc.contributor.author","Willig, Katrin I."],["dc.date.accessioned","2019-07-09T11:45:13Z"],["dc.date.available","2019-07-09T11:45:13Z"],["dc.date.issued","2018"],["dc.description.abstract","The post-synaptic density (PSD) is an electron dense region consisting of ~1000 proteins, found at the postsynaptic membrane of excitatory synapses, which varies in size depending upon synaptic strength. PSD95 is an abundant scaffolding protein in the PSD and assembles a family of supercomplexes comprised of neurotransmitter receptors, ion channels, as well as signalling and structural proteins. We use superresolution STED (STimulated Emission Depletion) nanoscopy to determine the size and shape of PSD95 in the anaesthetised mouse visual cortex. Adult knock-in mice expressing eGFP fused to the endogenous PSD95 protein were imaged at time points from 1 min to 6 h. Superresolved large assemblies of PSD95 show different sub-structures; most large assemblies were ring-like, some horse-shoe or figure-8 shaped, and shapes were continuous or made up of nanoclusters. The sub-structure appeared stable during the shorter (minute) time points, but after 1 h, more than 50% of the large assemblies showed a change in sub-structure. Overall, these data showed a sub-morphology of large PSD95 assemblies which undergo changes within the 6 hours of observation in the anaesthetised mouse."],["dc.identifier.doi","10.1038/s41598-017-18640-z"],["dc.identifier.pmid","29317733"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/15060"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/59184"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation","info:eu-repo/grantAgreement/EC/FP7/241498/EU//EUROSPIN"],["dc.relation.issn","2045-2322"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.subject.ddc","610"],["dc.title","In vivo STED microscopy visualizes PSD95 sub-structures and morphological changes over several hours in the mouse visual cortex."],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","S2211124721005386"],["dc.bibliographiccitation.firstpage","109192"],["dc.bibliographiccitation.issue","9"],["dc.bibliographiccitation.journal","Cell Reports"],["dc.bibliographiccitation.volume","35"],["dc.contributor.author","Willig, Katrin I."],["dc.contributor.author","Wegner, Waja"],["dc.contributor.author","Müller, Antonia"],["dc.contributor.author","Calvet-Fournier, Valérie"],["dc.contributor.author","Steffens, Heinz"],["dc.date.accessioned","2021-07-05T15:00:59Z"],["dc.date.available","2021-07-05T15:00:59Z"],["dc.date.issued","2021"],["dc.description.sponsorship","Open-Access-Publikationsfonds 2021"],["dc.identifier.doi","10.1016/j.celrep.2021.109192"],["dc.identifier.pii","S2211124721005386"],["dc.identifier.pmid","34077731"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/87954"],["dc.identifier.url","https://mbexc.uni-goettingen.de/literature/publications/262"],["dc.language.iso","en"],["dc.notes.intern","DOI Import DOI-Import GROB-441"],["dc.relation","EXC 2067: Multiscale Bioimaging"],["dc.relation.issn","2211-1247"],["dc.relation.workinggroup","RG Willig (Optical Nanoscopy in Neuroscience)"],["dc.rights","CC BY-NC-ND 4.0"],["dc.title","Multi-label in vivo STED microscopy by parallelized switching of reversibly switchable fluorescent proteins"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","eabf2806"],["dc.bibliographiccitation.issue","24"],["dc.bibliographiccitation.journal","Science Advances"],["dc.bibliographiccitation.volume","7"],["dc.contributor.author","Steffens, Heinz"],["dc.contributor.author","Mott, Alexander C."],["dc.contributor.author","Li, Siyuan"],["dc.contributor.author","Wegner, Waja"],["dc.contributor.author","Švehla, Pavel"],["dc.contributor.author","Kan, Vanessa W. Y."],["dc.contributor.author","Wolf, Fred"],["dc.contributor.author","Liebscher, Sabine"],["dc.contributor.author","Willig, Katrin I."],["dc.date.accessioned","2021-07-05T14:57:45Z"],["dc.date.available","2021-07-05T14:57:45Z"],["dc.date.issued","2021"],["dc.description.abstract","Excitatory synapses on dendritic spines of pyramidal neurons are considered a central memory locus. To foster both continuous adaption and the storage of long-term information, spines need to be plastic and stable at the same time. Here, we advanced in vivo STED nanoscopy to superresolve distinct features of spines (head size and neck length/width) in mouse neocortex for up to 1 month. While LTP-dependent changes predict highly correlated modifications of spine geometry, we find both, uncorrelated and correlated dynamics, indicating multiple independent drivers of spine remodeling. The magnitude of this remodeling suggests substantial fluctuations in synaptic strength. Despite this high degree of volatility, all spine features exhibit persistent components that are maintained over long periods of time. Furthermore, chronic nanoscopy uncovers structural alterations in the cortex of a mouse model of neurodegeneration. Thus, at the nanoscale, stable dendritic spines exhibit a delicate balance of stability and volatility."],["dc.identifier.doi","10.1126/sciadv.abf2806"],["dc.identifier.pmid","34108204"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/87727"],["dc.identifier.url","https://mbexc.uni-goettingen.de/literature/publications/265"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-441"],["dc.relation","EXC 2067: Multiscale Bioimaging"],["dc.relation.eissn","2375-2548"],["dc.relation.workinggroup","RG Willig (Optical Nanoscopy in Neuroscience)"],["dc.relation.workinggroup","RG Wolf"],["dc.rights","CC BY-NC 4.0"],["dc.title","Stable but not rigid: Chronic in vivo STED nanoscopy reveals extensive remodeling of spines, indicating multiple drivers of plasticity"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","290"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Nature Communications"],["dc.bibliographiccitation.volume","9"],["dc.contributor.author","Neef, Jakob"],["dc.contributor.author","Urban, Nicolai T."],["dc.contributor.author","Ohn, Tzu-Lun"],["dc.contributor.author","Frank, Thomas"],["dc.contributor.author","Jean, Philippe"],["dc.contributor.author","Hell, Stefan W."],["dc.contributor.author","Willig, Katrin I."],["dc.contributor.author","Moser, Tobias"],["dc.date.accessioned","2018-04-23T11:48:23Z"],["dc.date.available","2018-04-23T11:48:23Z"],["dc.date.issued","2018"],["dc.description.abstract","Ca2+ influx triggers the release of synaptic vesicles at the presynaptic active zone (AZ). A quantitative characterization of presynaptic Ca2+ signaling is critical for understanding synaptic transmission. However, this has remained challenging to establish at the required resolution. Here, we employ confocal and stimulated emission depletion (STED) microscopy to quantify the number (20–330) and arrangement (mostly linear 70 nm × 100–600 nm clusters) of Ca2+ channels at AZs of mouse cochlear inner hair cells (IHCs). Establishing STED Ca2+ imaging, we analyze presynaptic Ca2+ signals at the nanometer scale and find confined elongated Ca2+ domains at normal IHC AZs, whereas Ca2+ domains are spatially spread out at the AZs of bassoon-deficient IHCs. Performing 2D-STED fluorescence lifetime analysis, we arrive at estimates of the Ca2+ concentrations at stimulated IHC AZs of on average 25 µM. We propose that IHCs form bassoon-dependent presynaptic Ca2+-channel clusters of similar density but scalable length, thereby varying the number of Ca2+ channels amongst individual AZs."],["dc.identifier.doi","10.1038/s41467-017-02612-y"],["dc.identifier.gro","3142361"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/15588"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/13498"],["dc.language.iso","en"],["dc.notes.intern","lifescience updates Crossref Import"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","final"],["dc.relation.issn","2041-1723"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.title","Quantitative optical nanophysiology of Ca2+ signaling at inner hair cell active zones"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","015007"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Neurophotonics"],["dc.bibliographiccitation.volume","6"],["dc.contributor.author","Stahlberg, Markus A."],["dc.contributor.author","Ramakrishnan, Charu"],["dc.contributor.author","Willig, Katrin I."],["dc.contributor.author","Boyden, Edward S."],["dc.contributor.author","Deisseroth, Karl"],["dc.contributor.author","Dean, Camin"],["dc.date.accessioned","2019-09-23T14:31:03Z"],["dc.date.available","2019-09-23T14:31:03Z"],["dc.date.issued","2019"],["dc.description.abstract","Optogenetics has revolutionized the study of circuit function in the brain, by allowing activation of specific ensembles of neurons by light. However, this technique has not yet been exploited extensively at the subcellular level. Here, we test the feasibility of a focal stimulation approach using stimulated emission depletion/reversible saturable optical fluorescence transitions-like illumination, whereby switchable light-gated channels are focally activated by a laser beam of one wavelength and deactivated by an overlapping donut-shaped beam of a different wavelength, confining activation to a center focal region. This method requires that activated channelrhodopsins are inactivated by overlapping illumination of a distinct wavelength and that photocurrents are large enough to be detected at the nanoscale. In tests of current optogenetic tools, we found that ChR2 C128A/H134R/T159C and CoChR C108S and C108S/D136A-activated with 405-nm light and inactivated by coillumination with 594-nm light-and C1V1 E122T/C167S-activated by 561-nm light and inactivated by 405-nm light-were most promising in terms of highest photocurrents and efficient inactivation with coillumination. Although further engineering of step-function channelrhodopsin variants with higher photoconductances will be required to employ this approach at the nanoscale, our findings provide a framework to guide future development of this technique."],["dc.identifier.doi","10.1117/1.NPh.6.1.015007"],["dc.identifier.pmid","30854405"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/15860"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/62431"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.issn","2329-423X"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.title","Investigating the feasibility of channelrhodopsin variants for nanoscale optogenetics"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","11781"],["dc.bibliographiccitation.firstpage","1"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Scientific reports"],["dc.bibliographiccitation.lastpage","10"],["dc.bibliographiccitation.volume","7"],["dc.contributor.author","Wegner, Waja"],["dc.contributor.author","Ilgen, Peter"],["dc.contributor.author","Gregor, Carola"],["dc.contributor.author","van Dort, Joris"],["dc.contributor.author","Mott, Alexander C."],["dc.contributor.author","Steffens, Heinz"],["dc.contributor.author","Willig, Katrin I."],["dc.date.accessioned","2019-07-09T11:44:29Z"],["dc.date.available","2019-07-09T11:44:29Z"],["dc.date.issued","2017-09-18"],["dc.description.abstract","The study of proteins in dendritic processes within the living brain is mainly hampered by the diffraction limit of light. STED microscopy is so far the only far-field light microscopy technique to overcome the diffraction limit and resolve dendritic spine plasticity at superresolution (nanoscopy) in the living mouse. After having tested several far-red fluorescent proteins in cell culture we report here STED microscopy of the far-red fluorescent protein mNeptune2, which showed best results for our application to superresolve actin filaments at a resolution of ~80 nm, and to observe morphological changes of actin in the cortex of a living mouse. We illustrate in vivo far-red neuronal actin imaging in the living mouse brain with superresolution for time periods of up to one hour. Actin was visualized by fusing mNeptune2 to the actin labels Lifeact or Actin-Chromobody. We evaluated the concentration dependent influence of both actin labels on the appearance of dendritic spines; spine number was significantly reduced at high expression levels whereas spine morphology was normal at low expression."],["dc.identifier.doi","10.1038/s41598-017-11827-4"],["dc.identifier.pmid","28924236"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/14798"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/59023"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.issn","2045-2322"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.subject.ddc","573"],["dc.subject.ddc","612"],["dc.title","In vivo mouse and live cell STED microscopy of neuronal actin plasticity using far-red emitting fluorescent proteins."],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","L01"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Biophysical Journal"],["dc.bibliographiccitation.lastpage","L03"],["dc.bibliographiccitation.volume","106"],["dc.contributor.author","Willig, Katrin I."],["dc.contributor.author","Steffens, Heinz"],["dc.contributor.author","Gregor, Carola"],["dc.contributor.author","Herholt, Alexander"],["dc.contributor.author","Rossner, Moritz J."],["dc.contributor.author","Hell, Stefan"],["dc.date.accessioned","2017-09-07T11:46:54Z"],["dc.date.available","2017-09-07T11:46:54Z"],["dc.date.issued","2014"],["dc.description.abstract","We demonstrate superresolution fluorescence microscopy (nanoscopy) of protein distributions in a mammalian brain in vivo. Stimulated emission depletion microscopy reveals the morphology of the filamentous actin in dendritic spines down to 40 mu m in the molecular layer of the visual cortex of an anesthetized mouse. Consecutive recordings at 43-70 nm resolution reveal dynamical changes in spine morphology."],["dc.identifier.doi","10.1016/j.bpj.2013.11.1119"],["dc.identifier.gro","3142199"],["dc.identifier.isi","000329407700001"],["dc.identifier.pmid","24411266"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/11365"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/5632"],["dc.language.iso","en"],["dc.notes.intern","WoS Import 2017-03-10"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","final"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation.eissn","1542-0086"],["dc.relation.issn","0006-3495"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.title","Nanoscopy of Filamentous Actin in Cortical Dendrites of a Living Mouse"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.journal","eLife"],["dc.bibliographiccitation.volume","11"],["dc.contributor.author","Wegner, Waja"],["dc.contributor.author","Steffens, Heinz"],["dc.contributor.author","Gregor, Carola"],["dc.contributor.author","Wolf, Fred"],["dc.contributor.author","Willig, Katrin I."],["dc.date.accessioned","2022-04-01T10:00:22Z"],["dc.date.available","2022-04-01T10:00:22Z"],["dc.date.issued","2022"],["dc.description.abstract","Synaptic plasticity underlies long-lasting structural and functional changes to brain circuitry and its experience-dependent remodeling can be fundamentally enhanced by environmental enrichment. It is however unknown, whether and how the environmental enrichment alters the morphology and dynamics of individual synapses. Here, we present a virtually crosstalk-free two-color in vivo stimulated emission depletion (STED) microscope to simultaneously superresolve the dynamics of endogenous PSD95 of the post-synaptic density and spine geometry in the mouse cortex. In general, the spine head geometry and PSD95 assemblies were highly dynamic, their changes depended linearly on their original size but correlated only mildly. With environmental enrichment, the size distributions of PSD95 and spine head sizes were sharper than in controls, indicating that synaptic strength is set more uniformly. The topography of the PSD95 nanoorganization was more dynamic after environmental enrichment; changes in size were smaller but more correlated than in mice housed in standard cages. Thus, two-color in vivo time-lapse imaging of synaptic nanoorganization uncovers a unique synaptic nanoplasticity associated with the enhanced learning capabilities under environmental enrichment."],["dc.identifier.doi","10.7554/eLife.73603"],["dc.identifier.pmid","35195066"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/105414"],["dc.identifier.url","https://mbexc.uni-goettingen.de/literature/publications/451"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-530"],["dc.relation","EXC 2067: Multiscale Bioimaging"],["dc.relation.eissn","2050-084X"],["dc.relation.workinggroup","RG Willig (Optical Nanoscopy in Neuroscience)"],["dc.relation.workinggroup","RG Wolf"],["dc.rights","CC BY 4.0"],["dc.rights.uri","http://creativecommons.org/licenses/by/4.0/"],["dc.title","Environmental enrichment enhances patterning and remodeling of synaptic nanoarchitecture as revealed by STED nanoscopy"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","577"],["dc.bibliographiccitation.firstpage","1"],["dc.bibliographiccitation.journal","Nature communications"],["dc.bibliographiccitation.lastpage","9"],["dc.bibliographiccitation.volume","8"],["dc.contributor.author","Richardson, Douglas S."],["dc.contributor.author","Gregor, Carola"],["dc.contributor.author","Winter, Franziska R."],["dc.contributor.author","Urban, Nicolai T."],["dc.contributor.author","Sahl, Steffen J."],["dc.contributor.author","Willig, Katrin I."],["dc.contributor.author","Hell, Stefan W."],["dc.date.accessioned","2018-01-17T13:31:10Z"],["dc.date.available","2018-01-17T13:31:10Z"],["dc.date.issued","2017"],["dc.description.abstract","Fluorescence-based biosensors have become essential tools for modern biology, allowing real-time monitoring of biological processes within living cells. Intracellular fluorescent pH probes comprise one of the most widely used families of biosensors in microscopy. One key application of pH probes has been to monitor the acidification of vesicles during endocytosis, an essential function that aids in cargo sorting and degradation. Prior to the development of super-resolution fluorescence microscopy (nanoscopy), investigation of endosomal dynamics in live cells remained difficult as these structures lie at or below the ~250 nm diffraction limit of light microscopy. Therefore, to aid in investigations of pH dynamics during endocytosis at the nanoscale, we have specifically designed a family of ratiometric endosomal pH probes for use in live-cell STED nanoscopy.Ratiometric fluorescent pH probes are useful tools to monitor acidification of vesicles during endocytosis, but the size of vesicles is below the diffraction limit. Here the authors develop a family of ratiometric pH sensors for use in STED super-resolution microscopy, and optimize their delivery to endosomes."],["dc.identifier.doi","10.1038/s41467-017-00606-4"],["dc.identifier.pmid","28924139"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/16496"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/11717"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","final"],["dc.relation.eissn","2041-1723"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.title","SRpHi ratiometric pH biosensors for super-resolution microscopy"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]